Odd Blood Gas question?

[McPoyle]

So, I have a post v-fib arrest pt in the CCU, has a cool guard catheter in the right groin that was placed by interventionalists in CV lab, and an art line in his left wrist. Last night we were getting ScvO2 in the 75% range off the cool guard and SaO2 in the 98% range off the art line. Well, today I asked for another gas off the cool guard and it came back with sat of 97% and PaO2 of 140. At first I think "I must've not been clear on what I wanted" so I ask the nurse and they swear it was off the cool guard. Ok, no big deal, just ask her to send a second one. This time I watch her and she was right, of course, it was off the cool guard and it returns with the same values.

I'm confused why this would be? Gas of the art line nearly identical to the one off the cool guard... I thought maybe it had somehow migrated into an artery since last night, but when I transduce it I am getting a CVP waveform and pressures of ~15....

Any thoughts?

---

Members don't see this ad.

 

[OB1🤙]

Two possibilities. There could be a PFO or small ASD that the lumen you're drawing from is snuggling up against. Is there another more proximal port you can draw another sample off?

The other possibility, if this is one of the long catheters, is that someone overzealously slammed this bad boy in and got it down into the RV, up the PA into a wedge position. Again, draw a sample from and transduce a more proximal lumen. Maybe you'll shock yourself with a PA waveform...

 

[jdh71]

So, I have a post v-fib arrest pt in the CCU, has a cool guard catheter in the right groin that was placed by interventionalists in CV lab, and an art line in his left wrist. Last night we were getting ScvO2 in the 75% range off the cool guard and SaO2 in the 98% range off the art line. Well, today I asked for another gas off the cool guard and it came back with sat of 97% and PaO2 of 140. At first I think "I must've not been clear on what I wanted" so I ask the nurse and they swear it was off the cool guard. Ok, no big deal, just ask her to send a second one. This time I watch her and she was right, of course, it was off the cool guard and it returns with the same values.

I'm confused why this would be? Gas of the art line nearly identical to the one off the cool guard... I thought maybe it had somehow migrated into an artery since last night, but when I transduce it I am getting a CVP waveform and pressures of ~15....

Any thoughts?

Ok. So that is an arterial gas with pressures that place the cool guard firmly in the IVC. I'm wondering about a cool guard that has been put in through the femoral artery into the vein, and the port where you can draw back is sitting in the artery portion of the length of the cool guard, or perhaps the fistulous communication is enough that femoral blood is mixing with the venous blood enough to give you those numbers, though still seems high even in that situation. Did you ever figure this out? Also what FiO2 is this patient on?

 

[ORL10]

if it s cool guard catheter it isn't long enough to make it into the RV (they are like 20cm long, like a trialysis line). I have seen people create a fistula when going in the groin, especially if they are double stuck (femoral angio, then femoral vv catheterization) which can create an AV fistula. The patient is not on V-V ECMO with the avalon catheter right ?

 

[McPoyle]

Evidently CT showed it against the RA septum. So the working theory was that there was/is a PFO. But, I feel like we should've seen this on ECHO... It was pulled back three cm and we are again getting appropriate values.

 

[jdh71]

Evidently CT showed it against the RA septum. So the working theory was that there was/is a PFO. But, I feel like we should've seen this on ECHO... It was pulled back three cm and we are again getting appropriate values.

Unless you did a TEE, it wouldn't surprised me it as missed. Where I train all cooling caths go in the fem. Why did this one go in the IJ? (I'm assuming it was in the IJ)

 

[McPoyle]

Nope, this one went in the fem, I guess it's just long and was placed a bit higher than normal?

 

[jdh71]

Nope, this one went in the fem, I guess it's just long and was placed a bit higher than normal?

Was this patient SHORT?

 

[OB1🤙]

FWIW there exist cooling catheters of various lengths. Pretty sure some are ~40cm.

 

[bigdan]

FWIW there exist cooling catheters of various lengths. Pretty sure some are ~40cm.

Agreed. The CoolGard company (I think it's Zoll) makes a 45 cm catheter...

 

[Hernandez]

That's a long ass catheter if you're reaching the RV from the fem......

 

[jdh71]

midgets

catheterize the BRAIN!!